Bit-holder for braces



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Patented Oct. 8, 1889.

H N PARKER BIT HOLDER FOR BRAGBS.

(No Model.)

UNITED STATES yPATENT Fries.

I-IOMER NEWTON PARKER, OF WINOHENDON, MASSACHUSETTS, ASSIGNOR T O WILLIAM M. CALDWELL, OF BROOKLYN, NEW YORK.

BIT-HOLDER FoR BRACES.

SPECIFICATION forming part of Letters Patent No. 412,535, dated October 8, 1889.

Appncaion nea caoba 15, 188s.

To all whom it may concern:

Be it known that I, HOMER NEWTON PAR- KER, of Winchendon, in the county of Worcester and State of Massachusetts, have invented certainnew and useful Improvements in Bit-Holders for Braces, &c.; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, making a part of this specification, in which- Figure l is a diametri@ section of thebitstock in line of Fig. 3, showing the jaws closed in position .to hold the bit; Fig. 2, a similar `section in line y y of Fig. 4, showing the jaws opened to release it; Fig. 3, a bottom or end view of the bit-stock with jaws closed; Fig. 4, a similar view showing the jaws opened; Fig. 5, a section similar to Fig. 2 illustrating` a modification in the form of the head and jaws with the adjusting-sleeve run back to admit of the removal of the jaws and one of the jaws removed. Fig. 6 is a section illustrating a modification in the jaws and adjusting-sleeve,l and Fig. 7 is an elevation of one of the jaws shown in Fig. 6 detached.

My invention relates to the forms of bitstocks for braces, which are constructed with an angular socket to receive the end of the bit and with clamping-jaws to be closed upon its shank to clasp and firmly hold it, the jaws being fitted in grooves or recesses having curved bottoms, so that they may beA automatically thrown open by means of a contractile spring embracing their inner ends.

It has for its object to reduce the cost and increase the efficiency of this form of stock or holder by simplifying its construction, reducing the number of its parts, and providing for a positive movement of the jaws both in opening and closing by the action of the sleeve alone without the intervention of a spring.

It consists in the combination, with'a movable sleeve encircling the stock, of jaws pivoted loosely in' diametrically opposed recesses cut longitudinally in the stock, each jaw being dished or inwardly curved or recessed on its outer face, so as to be widened or enlarged at each end and afford unsup- Serial No. 288,107. (No modelJ ported bearing-surfaces at bot-h said ends to permit the same to be respectively borne inward by the inclosing sleeve as it is carried over them, whereby the movement of the .sleeve in either direction toward the ends of the jawswill operate positively to close said ends together and spread open the opposite ends.

It consists, furthermore, in the combination, with cach jaw, of screw-threads formed upon its outer face over the pivotal bearing thereof to engage the internally-threaded adjustinglsleeve fitted over the same.

In the accompanying drawings, A is the head or stock for the brace B. This stock is of the customary form, having a solid portion, in which is formed a central socket D, to receive the end of the shank of the bit or tool, (see Figs. l, 2, 4, and 6,) and a tubular cylindrical extension E, serving as a support for the adjusting-sleeve F, adapted to work lengthwise upon it; or the socket D may be omitted and the jaws formed so as to hold the bit alone, as shown in Fig. 5.

The jaws G Gr are fitted loosely in longitudinal recesses H H, cut in the stock at diametrically-opposite points thereof, and which are continued in the form of slots in the tubular portion E of the stock out to the end thereof. These clamping-jaws G G are long enough to extend to the end of the stock when fitted in the recesses H H. Their outer ends are of the customary form, adapting them to seize and hold the shank of the bit or tool to be held by the stock and shaped to conform externally when closed with the periphery of the stock, as shown in Fig. 3. Each jaw is .reduced centrally in thickness or otherwise inwardly dished or centrally recessed, so that each end of the jaw is made to widen or enlarge toward its extremity with an inclined surface, as shown at S S in the drawings. A transverse notch I (see Figs. 5 and 7) is preferably cut on the inner Aface of each jaw to partly embrace a pin or counterpart offset K, fitted or formed transversely in each recess H, near to the end of the solid portion of the head. These pins or offsets K K serve as pivots upon which the jaws may rock longi- IOO jaws are forced inward so as not to project beyond the periphery of the head theirouter ends will open wide to receive the bit or tool, as shown Ain Fig. 2; or if the outer ends be closed together the inner ends will be opened outV beyond the periphery of the head, as shown in Fig. l.

The external adjustingsleeve F, fitted to play upon the external periphery of the stock, is so proportioned in length as that When it is bearing upon one end of the jaws it will leave the opposite end free. It is internally threaded, and may work as usual upon a screw-thread cut upon the outer periphery of the stock, as shown in Figs. 1, 2, and 5. Preferably, however, the outer face of the stock is left plain, as shown in Fig. 6, and a short thread M is formed to project upon the outer face of each jaw immediately over its pivotal bearing, as shown in Figs. G and 7.

In the operation of the device the longitudinal movement of the sleeve F upon the stock A (eiected by turning it and caused by the engagement of its internal threads with the screw cut either externally upon said head, as in Fig. l, or upon the face of the jaws, as in Fig. 6) will, by carrying one end of the sleeve over the outwardly-diverging ends of the jaws, operate positively to close them inward, and thereby cause their opposite ends to open outward. Hence by screwing the sleeve inwardly upon the stock the jaws are caused to open to receive the bit or tool, as shown in Fig. 2, and by screwing` the sleeve outwardly the jaws are closed thereon to tightly clamp the same, as shown in Figs. l and 6. By running the sleeve inward far enough to clear the inner ends of the recesses H H the jaws may be readily lifted out, as shown in Fig. 5, for repair or renewal.

It is evident that the jaws may be made to rock upon transverse osets projecting from their inner faces into transverse grooves cut inthe inner face of the recesses H H, instead of vice versa, as liereinbefore described, and that the pivotal or bearing surface upon which the jaws are thus made to rock may be widened more or less without departing from my invention, which contemplates causing the jaws to rock from end to end in any effective manner without longitudinal 'displace- Inent. It is also evident that, it' occasion require, three or more jaws may be inserted, to operate as described, in a single head.

I claim as my invention l. The combination, in a bitholder, of the cylindrical head havinglongitudinal recesses in its periphery, a jaw mounted within each recess to rock, without longitudinal movement, upon a transverse pivotal support, so that one or other of its ends shall necessarily project beyond said periphery, and a sleeve fitted to move longitudinally upon the head into engagement with either projecting end of the jaw to force said end inward, substantially in the manner and for the purpose herein set forth.

2. The combination, in a bit-holder, of the cylindrical head having longitudinal recesses in its periphery, an extended jaw fitted in each recess to rock without longitudinal movement upon a transverse pivotal support, so that one or other of its ends shall necessarily project beyond the periphery, and having a screw-thread projecting from its outer face over its pivotal bearing, and a sleeve encircling the head and formed with an internal thread` to engage the thread on each pivotedjaw and be thereby carried, as it revolves thereon, longitudinally over the jaws and head, substantially in the manner and for the purpose herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HOMER NEWTON PARKER.

Witnesses:

GEO. M. WHITNEY, J. W. GoRHAM. 

